I have invented - "The Sizer"

It has always struck as a nuisance (I've been stricken) how often I'll see a semi-macro and think ... "Yes, but HOW BIG is it?" The casual observer may spot a ruddy great paw clutching a 10P coin from time to time. It occurred to me some time ago because:-
A ) Coincidentally it's almost exactly 1" or 25.4mm in diameter.
B ) It's as near as damnit is to swearing the same size as one of "their" $0.25¢ thingies.
Elsewise how do you know this is a teeny weeny one?
BTW - there's another, possibly teenier in th offing.
BTW#2 - IF you need to check, just cover the 10P with a piece of paper.